In new building construction, plumbers prefer not to install finished closure valves in the bottom of bathtubs, and not to install finished decorative plates over an overflow outlets of bathtubs, until the project is finished, because these elements otherwise may be damaged during construction. Additionally, newly installed plumbing systems typically must be tested before use to ensure the system functions properly and does not leak. Testing typically involves closing off all inlets to the plumbing system, and filling the system with air or water and inspecting the entire system for leaks. Various means for closing off the inlets to the plumbing system are known, including inflatable balloons, screw-on stoppers, and pre-installed skins or membranes that close off plumbing inlets and can be cut away or otherwise removed before to use. When one of these fluid flow stopping mechanisms is not readily available, plumbers sometimes plug a plumbing system inlet with rags or other available materials.
Existing bathtub overflow assemblies comprise an overflow pipe positioned on the outer (dry) side of a bathtub wall, and that fits against or through an overflow hole in the bathtub wall. An overflow plate or cap is provided on the inner (wet) side of the bathtub wall to conceal the overflow drain opening and present a finished look. Common prior art overflow assemblies provided a cross beam that spans the overflow pipes opening that communicates with the bathtub interior. Alternatively, overflow pipe openings employ protrusions on opposite sides of the interior opening. To connect the cover, a central screw or two laterally opposite screws are threaded through a corresponding central hole or laterally opposite holes in the overflow cap, and into a corresponding central hole provided in the cross beam or laterally opposed holes provided in the protrusions. In these assemblies, the necessity of providing a cross-beam with a central hole across the opening of the overflow pipe, or of providing screw holes on the inner wall of the overflow pipe, adds complexity and proves inconvenient for testing purposes. The central cross-beam prevents the use of, or at least increases the difficulty of placing, an inflatable balloon with the pipe, or of stuffing the pipe with rags or other materials. The laterally opposite protrusions on the inner wall of the pipe typically change the shape of the inner circumference of the pipe, thus preventing the use of round stoppers to plug the pipe.
Additionally, both the one-hole and the two-hole style overflow assemblies often can only be installed by two persons, particular where the overflow cap is not installed until construction is complete. This is because the overflow pipe typically will not stay in position unless the overflow cap has been screwed thereto, and when construction is complete or nearly so the back side of the tub is inaccessible from the front side of the tub and vice-versa.
In other overflow assemblies, including those described in many of the references specifically identified and incorporated by reference above, a portion of the overflow pipe passes through the overflow hole in the bathtub wall, thus helping the pipe to stay in place without screws. The portion of the pipe that extends through the bathtub wall may also be threaded, such that a nut can be tightened onto the overflow pipe to secure the overflow pipe to the bathtub wall. In these assemblies, an overflow cap may be sized to snap onto, or otherwise deflectably interconnect to, the nut; thus, facilitating installation of the overflow cover once construction is complete, while also providing an aesthetically pleasing finish (e.g. by concealing the nut and overflow pipe). Also in these assemblies, leak testing may be facilitated by incorporating a membrane over the end of the overflow pipe that closes the overflow pipe. Once testing is complete, the membrane can be cut or otherwise removed to allow fluid to flow through the overflow pipe. Even where such a membrane is not provided, the inner circumference of the overflow pipe is free of any obstacles, such as a cross-beam or protrusions for accommodating screw holes, and can therefore readily receive a stopper, an inflatable balloon, or other available stopping mechanisms. Installation of an overflow cap on the overflow pipe of these no-screw overflow assemblies can be accomplished by one person, from the bathtub interior.
While no-screw overflow assemblies represent a significant improvement over the more traditional one-hole and two-hole overflow assemblies, such assemblies may still present various challengers to an installer. For example, bathtub walls have varying thicknesses, such that the upper portion of an overflow pipe (i.e. the portion that fits through the bathtub wall) must be carefully sized. If the upper portion is too long, then the overflow pipe will extend too far into the bathtub, and the overflow cap will not cover the entirety thereof. If the upper portion is too short, then it may be difficult or impossible to thread a nut onto the upper portion to secure the overflow pipe in position.
Additionally, the overflow cap and nut must be precisely sized so the overflow cap, when pressed over the nut, stays in position. Depending on the desired size of the overflow cap, this may necessitate a nut that is larger than necessary, which may disadvantageously drive up the cost of the assembly.
Further, some persons find that the overflow cap does not fit onto the cap as cleanly as they would like, or with proper alignment.
Still further, some customers, including particularly hotels and other places that offer temporary accommodations, desire a more substantial locking mechanism for retaining the overflow cap in position over the overflow pipe, to prevent theft of the overflow cap or to prevent the inadvertent dislodging of the overflow cap from its proper position.